As automated assembly equipment and robots become more sophisticated, it is desirable to add the sense of vision to such devices. This would enable the equipment to locate the position of the object being manufactured as well as inspect the object for the presence of components or the proper location and size of specific features such as holes. To this end video cameras have been employed to generate a video image of the workpiece which then can be electronically analyzed.
One of the problems that is encountered in vision systems used with an automated assembly process is that the workpieces may vary in position as they move along a conveyor system or other type of material handling equipment. Typically, in order for the workpiece to be properly evaluated, it must be accurately positioned with respect to the video camera. When the proper location is critical in conventional manufacturing systems, the workpiece is placed in a fixture which locates it very accurately with respect to the manufacturing equipment such as a component insertion machine. However this fixture adds expense and time to the manufacturing process.
Human beings working on an assembly line do require that the workpiece be accurately aligned with respect to them. People are able to recognize the location of the various components within their field of view and adapt to variations in location as different workpieces placed in front of them. It is desirable to afford a vision system with this attribute of the human assembly worker enabling it to tolerate some degree of workpiece misalignment.